The invention relates generally to telecommunications, and more particularly to access network with an integrated splifter.
Telephone customers are moving in an evolutionary way to higher bandwidths, from sharing POTS (Plain Old Telephone Service) and modem on one line to dedicated analog modem line at 33.6 kbps, to dedicated analog modem line at 56 kbps, and then to ISDN BA (Basic Access). Now, ADSL (asymmetrical digital subscriber line) has been introduced, and the ADSL modems have become proven technology. ADSL refers to the two way capability of a twisted copper pair with analog to digital conversion at the subscriber end and an advanced transmission technology. Ordinary twisted pair equipped with ADSL modems can transmit movies, television, dense graphics, and very high speed data. For all its capacity, ADSL leaves POTS (Plain Old Telephone Service) undisturbed. A single ADSL line therefore offers simultaneous channels for personal computers, televisions, and telephones. With ADSL, telephone companies can connect almost every home and business to exciting new interactive broadband services. The recent announcement of the Universal ADSL has accelerated the interest in the UADSL technology and will speed up of introducing UADSL in large volume.
The ISDN and ADSL services are different. ISDN provides two voice channels or a 128 kbps data channel while ADSL is predominantly a data pipe providing an asymmetrical bandwidth of up to 9 Mbps downstream and 800 kbps upstream. An ADSL access network will be an overlay network and therefore not require the expensive and time-consuming switch upgrades that held ISDN back for so long.
The customers for ADSL most likely already have a dedicated modem line or ISDN. A large proportion of the future customers will be connected to pair gain systems in the US or to ISDN in Europe.
FIG. 1 shows a standard ADSL configuration. At a telephone company location 100, a central office terminal (COT) 2, such as a line card, provides an analog telephone line POTS. An ADSL modem 4, which receives broadband data from the Internet, for example, provides ADSL. Both the POTS and ADSL are connected to a splifter 6, which provides both the POTS and ADSL services to a customer premise 200. A splitter 8 receives the POTS and ADSL signals and separates them. The ADSL provided from splitter 8 is connected to an ADSL modem 10, which is connected to either ATM 25 (asynchronous transfer mode 25 Mbps) or Ethernet. Splitters 6 and 8 are bidirectional. In other words, splitter 8 also integrates the POTS and ADSL into a single pair of lines. The single pair of lines is connected to splitter 6, which separates it to POTS and ADSL lines and provides them to COT 2 and ADSL modem 4, respectively. In this configuration, two splitters 6 and 8 are needed, one at telephone company location 100 and the other at customer premise 200.
FIG. 2 shows a configuration of UADSL, i.e., splitterless ADSL. In this configuration, no splitter is required at customer premise 200. A UADSL modem 14 is connected in parallel with an analog telephone equipment 12. UADSL modem 14 will work simultaneously with telephone equipment 12, i.e. also during ringing, dial pulsing, etc. The bit rate of UADSL modem 14 will be significantly lower compared to full-rate ADSL, but there will still be an improvement of 20-25 times over the actually achievable bit rates with analog modems.
FIG. 3A shows a configuration of ADSL over a pair gain system. In this configuration, at telephone company location 100, COT 2 provides two pairs of POTS lines to a pair gain line card (LC) system 16, which converts the two pairs into one DSL (Digital Subscriber Line). The DSL and ADSL supplied from ADSL modem 4 are connected to splitter 18, which provides DSL and ADSL services to customer premise 200 on a single pair of lines. At customer premise 200, splitter 20 separates the DSL from the ADSL. The DSL is provided to a pair gain remote terminal (RT) 22, which provides two analog POTS lines. The ADSL is provided to ADSL modem 24, which is connected to either ATM 25 or Ethernet. Because of the difference in frequency use, remote power feeding, etc., there will always be a need for splitter 20 at customer premise 200 side with pair gain systems even with UADSL transmission. In the case of providing ADSL over ISDN BA (basic access), pair gain remote terminal 22 can also be an ISDN NT1 (network termination 1).
FIG. 3B shows a standard remote terminal 22. Connectors 1, 2 and DSL are connected to POTS 1, POTS 2, and DSL lines, respectively.
In the conventional configurations, such as shown in FIGS. 1 and 3A, an external splitter is required at customer premise 200. The external splitter is usually located in a sealed box. However, an external splitter at the customer premise means an extra box at or in the house. Furthermore, using an external splitter as a separate device involves a number of operational and administrative issues, such as ordering, provisioning, maintenance, customer service, billing, testing, etc. Thus, when a customer orders ADSL service, all these issues need to be resolved. This presents significant operational and administrative costs to Telecom operators.
Therefore, there is need for an integrated remote terminal that reduces the operational and administrative costs associated with providing ADSL services to customers.